• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.462-472
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• 2023

We investigated the physio-chemical and geochemical parameters in the spraying shellfish aquacultures (Yeoja and Gangjin Bay) to establish the systematic strategy for effective environmental management. Spatial variation of each parameter showed partially significant difference (P<0.05) between Yeoja and Ganjin Bay, inferring the discriminative progress (i.e., accumulation and degradation) of the autochthonous organic matter within the aquaculture environments. We additionally integrated various properties (e.g., water/sediment quality, natural hazard, and biological health) which may affect the biological growth within the aquaculture habitats based on the biogeochemical cycles related to environmental components and aquaculture species. We used a screening approach (i.e., one out-all out; OOAO) which can permit the assessment of the health levels of aquaculture species, the scoring for other parameters (seawater, sediment, and natural hazard) as three levels (excellent, moderate and poor) depending on the complex interactive properties occurring in the aquaculture environments. Actual, discriminative scores obtained via our case studies may confirm that these stepwise processes are effectively evaluated for optimal health conditions within the aquaculture habitats. Thus, this approach may provide valuable insights for effective environmental management and sustainable growth of aquaculture operation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.735-745
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• 2022

In this study, a health assessment was conducted using the Benthic Health Index (BHI) to assess fish cage farms, where a fishery environment assessment was also performed. A total of 43 farms were evaluated located in the East Sea, West Sea, and South Sea in Korea. The results of the BHI health evaluation included 8 grade 1 farms, 4 grade 2, 12 grade 3, and 19 grade 4. The grade 1 farms included sandy sediment farms and those with low intensity aquaculture, while the grade 2 farms included those located in areas with active seawater circulation. The fish cage farms belonging to grade 3 and 4 included the majority of farms with high-intensity aquaculture activities. There was no significant difference in total organic carbon between grade 3 and 4 farms, but the results of polychaete community analysis show that organic matter concentration was significantly higher in grade 4 farms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.598-611
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• 2022

The aim of this study was to investigate the range of influence of aquaculture activities in fish cage farms located on the southern coast of Korea (Farm A and B in Hadong, Farm C in Tongyoung, and Farm D in Geoje) by analyzing the distribution and characteristics of polychaete communities. Farm A and B showed remarkably high aquaculture intensity, and as a result, the polychaete communities near the farms were heavily polluted. However, there was a difference in the polychaete communities at a distance greater than 30 m from farm A and B, which may be due to topographical differences. The effect of the aquaculture activity of Farm C was only observed below the farm, however, the influence of aquaculture activities Farm D was maintained over a relatively long distance. According to the results of this study, the effect of the fish cage culture was mainly influenced by factors related to the production of fish, such as the stocking amount and the amount of food supply. Moreover, the distance at which the influence of aquaculture activity was observed was found to be closely related to the topographical characteristics and flow velocity around the farms.

• The Korean Journal of Malacology
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• v.30 no.3
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• pp.189-196
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• 2014

A significant production decrease has been witnessed for the Pacific oysters, Crassostrea gigas farmed in the western coastal waters of Korea, presumably by the loss of physiological viability. We evaluated the viability in terms of health indicators, the condition indices and hemocyte apoptosis rates of the oysters inhabiting two representative farming sites, Incheon and Taean each with different environmental variables. In our monthly measurements for the whole year 2013, the indicators were location specific. The condition indices of Incheon were highly variable, 1.67-8.58%, while those of Taean were less, 2.28-5.57%. The condition indices decreased during the spawning seasons, July and September in common. The two oysters exhibited also differed in the apoptotic activities of hemocyte, highly active, 4.03-30.15% for Incheon oysters and less active, 2.87-17.48% for Taean oysters. One thing we could identify was the two measurements were adverse during the critical seasons of spawning, reminiscent of being a useful tool for a health indicator for the oysters. Similar trend was also observed in the time when change in temperature was extreme. The findings in this study are highly indicative of health indicators for the oyster aquaculture.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.779-793
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• 2023

Intensive and long-term aquaculture activities in Korea have generated considerable amounts of organic matter, deteriorating the sedimentary environment and ecosystem. The Korean government enacted the Fishery Management Act to preserve and manage the environment of fish farms. Based on this, a fisheries environment assessment has been conducted on fish cage farms since 2014, necessitating the development of a scientific and objective evaluation method suitable for the domestic environment. Therefore, a benthic health index (BHI) was developed using the relationship between benthic polychaete communities and organic matter, a major source of pollution in fish farms. In this study, the development process and calculation method of the BHI have been introduced. The BHI was calculated by classifying 225 species of polychaetes appearing in domestic coastal and aquaculture areas into four groups by linking the concentration gradient of the total organic carbon in the sediment and the distributional characteristics of each species and assigning differential weights to each group. Using BHI, the benthic fauna communities were assigned to one of the four ecological classes (Grade 1: Normal, Grade 2: Slightly polluted, Grade 3: Moderately polluted, and Grade 4: Heavily polluted). The application of the developed index in the field enabled effective evaluation of the Korean environment, being relatively more accurate and less affected by the season compared with the existing evaluation methods like the diversity index or AZTI's Marine Biotic Index developed overseas. In addition, using BHI will be useful in the environmental management of fish farms, as the environment can be graded in quantified figures.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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• pp.481-486
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• 2009

In 2007, 43.5% mortality of the cultured oyster population occurred in Gamak Bay. Mortality rapidly increase in September and peak in October. To prevent future mass-mortality event, we investigated spawning and variation of oyster body composition. The main spawning period of culture oyster occurred from August to September. Condition index and body composition (protein and glycogen) appeared to be influenced by the spawning activity. Condition index and glycogen content in September were lowest (13.5% and 5.6 mg/g, respectively). However, protein, lipid and glycogen contents did not rapidly recover after the spawning activity. The data indicates that mass-mortality of cultured oysters in Gamak Bay may be due to deteriorated health, spawning activity, stress of the high water temperature and decreasing food resources.

• Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.233-239
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• 2012

Hematological analysis can provide crucial information for monitoring the health of fish. However, there is no current information available regarding hematological changes in olive flounder following infection by Vibrio scophthalmi. In this study, hematological and biochemical alterations were determined in olive flounder infected by the high virulence strain (HVS) and low virulence strain (LVS) of V. scophthalmi. Survival in serum, skin mucus, and macrophages of olive flounder was also compared between the HVS and LVS. The results demonstrated that the hematocrit value in infected fish declined from 23.4% at 0 h to 18.0% at 168 h post infection. The total protein concentration in fish infected with the HVS was significantly higher than in fish infected with the LVS and a non-infected control. Lysozyme activity was significantly different between infected and control fish. The HVS survived in serum and cell numbers increased substantially, while cell numbers of the LVS in serum decreased. These changes in hematological characteristics in fish infected by V. scophthalmi can be used as an effective and sensitive index to monitor the physiological and pathological conditions of fish. The survival and reproduction of V. scophthalmi in host serum, skin mucus, and macrophages play a major role in systemic infection and can serve as a virulence indicator for different strains.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.20-31
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• 2024

This study was conducted to investigate the changes in the structure of benthic communities resulting from aquaculture activities and to assess the benthic health status of surface sediment in Gangjin Bay, a region known for concentrated shellfish aquaculture on the southern coast of Korea. Survey stations were divided into longline culture, bottom culture, and non-cultivation areas. The spatiotemporal distribution of physiochemical factors such as the grain size, water temperature, salinity, and total organic carbon in Gangjin Bay showed no significant differences between sampling stations. However, the species number, density, and diversity were relatively lower at the sampling stations in the bottom culture areas than at the other stations throughout the entire survey period. Cluster analysis and principal coordinates analysis also clearly distinguished the benthic communities in the bottom culture areas from those in the other sampling areas. At the sampling stations in the longline culture and non-cultivation areas, Scolectoma longifolia and Sigambra tentaculata, which are indicator species of organically enriched areas, appeared as dominant species. However, excluding some stations influenced by physical factors such as the water depth and current speed, the occupancy rate was not high. The health assessment results, conducted using the fisheries environment assessment method, revealed good conditions with Grades 1 and 2 across the entire area. However, an examination of the spatiotemporal changes in benthic communities and the benthic health index indicated that the benthic environment in the bottom culture areas was affected by physical disturbances.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.835-842
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• 2022

Several countries are establishing management systems for aquaculture environment, and fishery environment assessment is one of them. The fishery management law amended in 2013 stipulates that a fishery environment assessment should be performed when a fish cage farm's license is extended. The purpose of the fishery environment assessment is to promote sustainable fishery, increase the fishery production capacity, and increase the fishermen incoming by implementing evaluation and improvement measures through scientific methods. The analysis items of fishery environment assessment include the Benthic Health Index (BHI), which is a biological index based on the macrobenthic polychaetes community, and total organic carbon (TOC), and the two items are scored and used for evaluation as a single grade. This study explains the selection process of BHI and TOC, which are evaluation items for fishing ground, and ecological significance of the calculated evaluation grades.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.1
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• pp.63-76
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• 2020

This study was conducted to quantitatively evaluate and analyze the alternative habitats using the HSI(Habitat Suitability Index) model of Lutra lutra in Banbyeoncheon Stream. Six variables were selected as habitat variables for Lutra lutra, including distance from waterfront, land cover within 1km from waterfront, presence of alluvial island, area of inland water and wetland, distance from roads and urbanized arid areas, and distance from aquaculture farm. The SI(Suitability Index) model and HSI model were developed based on the existing literature of Lutra lutra, the results of field surveys and expert opinions, and applied to the alternative habitats to examine the applicability of the HSI model. The results of this study can provide information on habitat evaluation to prevent the extinction of endangered Lutra lutra. In particular, it is highly applicable to the selection and evaluation of alternative habitats for Lutra lutra.